I mentioned it before...I don't think these pop songs that are tacked on to the end credits of a film should be eligible. I'd rather see songs nominated that were actually sung as part of the story of the film...or at a minimum, something that was played during the film itself that made an artistic contribution to the story. "Let it Go" plays a crucial role in Frozen and is a big part of the story. Other than U2 saying the song is about Mandela (a dubious claim IMO) the song contributes absolutely nothing to that movie, and in fact the movie would play exactly the same (but for the credits) without the song. So how does that add to the film at all? I don't know, that's kind of lame to me, and not fair to the artists who actually worked at making a piece of music that was part of a film's story and contributed to the final on-screen product in a meaningful away.
The way U2's song is being considered, it's more like a Grammy...an award for the song itself, but not how good it works in terms of the film. There really should be a distinction, and I actually hope that's something the Academy voters keep in mind, because while I like U2's song better than any of the other songs (I guess), I don't think they deserve to win (though they probably will).